Disclosed are apparatus and methods for quantifying the value of purchasing a particular search keyword, so that a particular search result is presented in a sponsored search results list for that particular search term, as compared to not purchasing the particular search keyword. In example embodiments, the quantified value of the particular search term indicates the particular search term's incremental value when the particular search result is presented in the sponsored search result list, as compared to when the same particular search result is not presented in such sponsored search result list. The particular search term's incremental value is based on a difference between the sum of the number of searchers who select the particular search result from the sponsored search list and the algorithmic search list, if any, versus the number of searchers who select the particular search result when it is not presented in the sponsored search list and may be only presented in the algorithmic search results.